GI Tract Physiologic
Disturbances
Intestinal Obstruction
• Obstruction to the antegrade flow of
intestinal contents
• Mechanical
– Blockage within the lumen
– Blockage from outside of the lumen
• Ileus – non mechanical
– Paralysis of the intestine
• Trauma
• Neurologic
• Inflammatory
Mechanical Obstruction
Small Intestine
• Small intestine dilated > 3 cm with gas
(swallowed air) and fluid (excreted by
digestive glands). Forms multiple air/fluid
levels
• Plain abdominal films (erect and supine
view) to confirm the diagnosis
Mechanical Obstruction
Small Intestine
• Observing number, location and mucosal
pattern of the dilated bowel may roughly
indicate the point of obstruction
• Commonly due to post-surgical adhesion
or hernia
Mechanical Small
Intestine
Obstruction
• Plain film
supine
• Distended gas
filled loops
Mechanical
Small Intestine
Obstruction
• Upright film
• Multiple air-fluid
levels
• Step laddering
(differential air fluid
levels)
• Prominent mucosal
folds - edema
Mechanical Obstruction
Large Intestine
• Distended colon from cecum to
level of obstruction with air and fluid
inside
• If you have an “Incompetent”
ileocecal valve, gas flow retrograde
into small intestine
Mechanical Obstruction
Large Intestine
• Barium enema to confirm the diagnosis
• Commonly due to
– Cancer
– Volvulus
• Child – midgut volvulus
• Adults – cecal volvulus
• Elderly – sigmoid volvulus
Distal Colon
Obstruction
• Supine
• Dilated colon
in ascending
and proximal
transverse
portions
Distal Colon
Obstruction
• Upright view
• Multiple air fluid
levels
Paralytic (Adynamic) Ileus
• The intestinal lumen is patent
• Functional defect
• Decreased propulsion, generalized or
localized
• Large and small intestine dilatation,
occasionally stomach dilated
Paralytic (Adynamic) Ileus
• Commonly due to intra-abdominal
inflammation, post surgical or posttraumatic reaction, spinal injury
• Can be generalized or localized
Paralytic
(adynamic) Ileus
• Supine film
• Dilatation of both
large and small
intestine
• Long tube coiled
in stomach
Pneumoperitoneum
• Free air in the peritoneal cavity
• Commonly due to:
– Perforation of gastrointestinal tract – peptic
ulcer
– Following surgical procedure – laparotomy
– Following laparoscopy
Pneumoperitoneum
• X-ray signs:
– On erect abdominal or chest film,
• a curvilinear (small amount) or a
crescent (moderate amount) of low
density beneath the opacity of the dome
of the diaphragm and the liver on the
right
–Most reliable sign
Pneumoperitoneum
• X-ray signs:
– Severely ill patient, one who cannot
maintain an erect position
• Perform a lateral decubitus film.
• The air floats to the top of the peritoneal cavity
forming a crescentic lucent area between the
abdominal wall and adjacent organs
Pneumoperitoneum
• X-ray signs:
– With no additional gas introduced, or other
complicating condition the free air will be
absorbed in 7-10 days in adults or much
faster 1-2 days in children
Pneumoperitoneum
• PA chest upright
• Curvilinear area
between right
diaphragm and
the liver (arrows)
• Small amount of
free air on the left
(single arrow)